In the push for ever decreased size and increased density and switching speed in microelectronic devices, researchers have constantly sought ways to construct smaller charge carriers with high carrier mobility. Graphene has shown promise as an extremely attractive material for such microelectronic applications. For example, it exhibits intrinsic mobilities of the order of 10 m2/Vs, two dimensional charge carrier concentrations of the order of 1012/cm2 at room temperature, and carrier velocity of 106 m/s, which would enable transistor operation at THz speeds. However, interactions with support materials, over-layers and the environment are known to negatively impact its transport characteristics.
Graphene is a single atomic sheet of graphitic carbon atoms that are arranged into a honeycomb lattice. It can be viewed as a giant two-dimensional Fullerene molecule, an unrolled single wall carbon nano-tube, or simply a single layer of lamellar graphite crystal. While the intrinsic mobility of graphene is limited by scattering with longitudinal acoustic phonons in its lattice, devices fabricated so far have been subject to additional scattering sources. The dominant sources of extrinsic scattering are long range scattering centers such as charged impurities on or near its surface and remote interfacial phonons originating from the support or over-layers. Other contributions to scattering arise from short range scattering centers such as point defects and corrugations of the lattice.
Therefore, there is a need for a structure that can allow the practical application of a material such as graphene, while mitigating the above described challenges resulting from the effects of scattering and other issues inherent in the use of graphene.